1. Field of the Invention
The present invention relates to a spacer for a linear guideway, and more particularly to a synchronous spacer with a guiding block, which prevents the occurrence of interference while improving the stability of the linear guideway.
2. Description of the Prior Art
Linear guideway is used more and more widely in modern industries. In addition to its high precision transmission performance, the linear guideway also has many other advantages, such as low friction loss, high ratio of energy conversion, low noise, high rigidity and wear-resistance. Therefore, it is self-evident that the linear guideway is very important to various industrial mechanisms. Normally, various linear guideways are provided with sliding bock, rail, and rolling elements that are used for linear and rotary application. However, to obtain the following objectives:
1, preventing the rolling elements from falling off the sliding block when taking the sliding block away from the rail;
2, preventing the rolling elements from touching one another, increasing the friction force thereof;
3, enabling the rolling elements to be arranged in an array, so that they can roll smoothly;
the current method is to put the rolling elements one by one into a chain of synchronous spacers, and the rolling elements are separated by the spacers.
One common method is shown in FIGS. 1 and 2, the synchronous spacer 10 includes a plurality of spacer elements 11 and a link 12. Each of the spacer elements 11 has two angular edge formed at both sides thereof. When the synchronous spacer 10 moves within the linear guideway, it will have the two following problems:
Firstly, when the synchronous spacer 10 moves from the circulating groove A of the loading area to the return portion B, since there are two spacer elements 11 and the link 12 at both ends of the synchronous spacer 10, plus each of the spacer elements 11 has two angular edges formed at both sides thereof, the spacer elements 11 will move linearly into the return portion B, impacting the inner surface B1 thereof, and then move along the inner surface B1 of the return portion (as shown in FIG. 1). Further, the spacer elements 11 and the link 12 at both ends of the synchronous spacer 10 will impact the connecting portion D (the assembly clearance) between the return portion B and the circulating groove A. Therefore, the synchronous spacer 10 cannot move smoothly into the return portion B.
Secondly, when the synchronous spacer 10 moves from the return portion B to the circulating groove A of the loading area, since there are two spacer elements 11 and the link 12 at both ends of the synchronous spacer 10, plus each of the spacer elements 11 has two angular edges, the spacer elements 11 will move into the circulating groove A in the tangent direction thereof, impacting the inner surface C of the circulating groove A, and then move linearly along the inner surface C (as shown in FIG. 2). Therefore, the synchronous spacer 10 cannot move smoothly into the return portion B, causing unstable motion of the rolling elements 13.
Thirdly, when the spacer 10 circulates within the linear guideway, the rolling elements 13 cannot move along the predetermined path due to the influence of impact and interference, and the rolling elements 13 will be subjected to many times of impact during movement, thereby seriously affecting the operation of the linear guideway.
To solve the abovementioned problems, another spacer structure was disclosed in U.S. Pat. No. 6,155,718, as shown in FIGS. 3 and 4, wherein the synchronous spacer 10 includes a plurality of spacer elements 11 and a link 12. The link 12 is formed at both ends 121 thereof with a curved guiding portion 122, and each of the spacer elements 11 is formed at either end thereof with a chamfer 111. This design can solve the abovementioned problems, however, it still has the following disadvantages:
Firstly, when the synchronous spacer 10 moves from the return portion to the circulating groove of the loading area, although the link 12 is formed with the curved guiding portion 122, and the spacer elements 11 are formed with chamfer 111, the connecting portion between the link 12 and the spacer elements 11 is still formed with vertical portion and angular edge, the spacer elements 11 cannot move into the circulating groove A smoothly in the tangent direction thereof, causing interference at the connecting portion (the assembly clearance) between the return portion and the circulating path.
Secondly, in addition to the fact that the vertical portion is formed at the connecting portion between the link 12 and the spacer elements 11, the spacer element 11 is smaller than the synchronous spacer 10, while the link 12 is larger than the synchronous spacer 10, therefore, the synchronous spacer 10 and the link 12 cannot guide the rolling elements 13 smoothly. The rolling elements 13 will deviate from the predetermined path and will be subjected to many times of impact during movement, thereby seriously affecting the operation of the linear guideway, and even causing noise.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.